Researchers at Northwestern University have developed a new method for recycling plastic that is safer, cleaner, cheaper, and more sustainable than those currently in use. The U.S. is the world’s largest plastic polluter per capita, and we only recycle 5% of our plastics. There is a pressing need for better technologies for processing different types of plastic waste.
The Northwestern method is designed to break down polyethylene terephthalate or PET, which is the most common type of polyester plastic. PET plastic is used in food packaging and beverage bottles and represents 12% of total plastics used globally. It does not break down easily and is therefore a major contributor to plastic pollution. It mostly either ends up in landfills or, over time, degrades into tiny microplastics or nanoplastics that end up almost everywhere.
The non-toxic, environmentally friendly, solvent-free Northwestern process first uses an inexpensive molybdenum catalyst to break apart the bonds in PET. Then the broken plastic is exposed to ambient air. Just from the trace amounts of moisture in air, the broken-down PET is converted into monomers, which are the building blocks of plastic. The monomers could then be recycled back into PET products or used to make other valuable materials.
The process is fast and effective and takes just a few hours. The catalyst is durable and recyclable, meaning it can be used over and over again. It only works on polyesters, which means it can be used for recycling mixed plastics without sorting them since it will select only the PET from its inputs.
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Plastic recycling gets a breath of fresh air
Photo, posted August 10, 2013, courtesy of Lisa Risager via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
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